#5



Trying to track small hesitation/ misfire. No codes on Ultra Gauge. Just turned 62k.

Completed tasks last 1- 2 years:

- Kingsbourne wires
- Bosch coil packs
- Intake gaskets & valley pan
- Purge Valve
- Downpipe gaskets both
- Valve cover gaskeys
- T- body bypass
- O2 upstream Bosch

I bought a injector kit off EBay to replace thimble filters, O rings and plastic clip. Noticed that the injector slipped in housing a little easier than with the original O rings. Wondering if I should have sent them out to be flow tested. Here are photos of the Champion plugs with about 3-5k on them. I installed NGK BPR6ES after reading reviews. It drives smooth and yet I feel that slight miss still. I have tried Champions, E3 and now NGK. Not the plugs... miss still follows. I feel it more during the day at a light in hot weather... 90's here.

You can see black marks on the insulator of #'s 1,3,5 & 8 with 5 being the worst. There is also a white color on the tip. I recently replaced the expansion tank and bypassed the t-body plate. I have not seen the level drop and my temps are 188- 194F driving and up the 199F at a light in 90F weather.

Photos-

 

I have the dreaded misfire as well and can't place it. Would really like to see what this digs up.

 

If I remember correctly, the white is caused by a lean condition. Something may be making her run a little lean, at least on those cylinders.

 

Did you adjust the gap on those champion plugs b4 instal? it should be 1mm = .040 inches,
It looks a little more in picture, (but I could be wrong, since I am just eyeballing from pic), if too much open will result in weaker spark that could explain white sooth,, good color for spark plug tip's is battleship gray, with very little to no black sooth on insulator that cant be wiped off easily,, and what is their heat range? for rover V8 ideal heat range is 7, if you use too hot of a spark plug it will foul when engine temp goes up, & you might notice a little misfire, (but not too much) & if too cool it will build up dark carbon on insulator that comes off easily,,

 

Try checking the connections on the coil packs if seated properly. Could just be loose since 1-2years you had it done. It might help just changing the plugs.

 

Thanks guys for the tips! I have a new hunch. Upon first start there is a rattle in the driver side cat. Once it heats up it goes away. Not sure how long it has been this way. I remember chasing a vacuum leak before I did all of the work. It posted codes. Ended up being intake gasket. Ran lean for awhile. Replaced both upstream sensors...later due to a code this past year. Also possible coolant may have fried my O2. My temps are fine and no coolant loss other than previously the t-body plate.

Crazy to think my driver side cat is damaged but the rattle is there with only 62k. Going to have to fix it when I can afford it. No codes now but the condition of the plugs on the driver side are obvious.

 

Someone can correct me if I am way off base, but cat rattle that early (assuming it wasn't whacked when off-roading) is probably because the cat got way too hot, such as fuel bring burned in the cat. If you were not firing on a cylinder that might cause gas to get to the cat where it would burn up, cracking the cat. In college I shorted out the front 3 injectors when I pinched a wire for them putting the upper intake back on. I was basically running on 3 cylinders until I found the problem. When it was running on only the back 3, the cat would be glowing red when I parked the car. I had cat rattle in that car after that.

 

im a little confused. are you attributing the bad cat to your odd colored plugs? i wouldn't think it would have anything at all to do with it as cat efficiency has no bearing on tuning.

but since it is in fact toast, why not just pay 20 bucks to have a strait pipe welded in?

 

Update-

I pulled the upper intake off... got a whiff of gas. Decided to swap back to the original black O rings on the injectors. The photo does not show it great but I don't think the brown O rings were exact size vs the original. The rail pulled right off with the brown injectors. It felt tighter seating the injectors with the black O rings. Not saying that this was the problem but it is peace of mind... for now.

I rechecked the wire connections at both coil packs. Double checked the wire layout to make sure it was Correct. I did not have a brain fart. I gapped at .040 and installed the Autolite Iridiums XP3924. Pulled the NGK BPR6ES. The Autolite uses the same socket as the Champions which was easier to get around the SAI pipes. The NGK used a larger socket which was tight using the socket and extension. Broke one of the plugs removing it. Got lucky it was loose enough to remove. Idle feels better... for now 🤞.